(Also, AFAIK, formats aren't disappearing from Perl6 - they're just moving from the core language to a module.)

Correct. However the syntax and semantics of the formatting facilities provided by that module will also differ from those of Perl 5 formats. See the Text::Reform module for a foretaste of the new approach (though Perl 6 formats will also differ somewhat from the syntax and semantics that module currently provides)